Compression in communications

ABSTRACT

Methods and apparatus are provided for processing communication traffic that includes a plurality of traffic units, each traffic unit having a header and a payload. In one embodiment, header compression is selectively applied to headers of traffic units from the communication traffic, and bit-level bulk data compression is selectively applied to the communication traffic. The bit-level bulk data compression involves accumulating blocks of bits, including headers and payloads of traffic units from the communication traffic, and operating on each block individually. In another embodiment, bit-level bulk data decompression is selectively applied to the communication traffic, and header decompression is selectively applied to headers of traffic units from the communication traffic. The bit-level bulk data decompression involves accumulating blocks of bits, including headers and payloads of traffic units from the communication traffic, and operating on each block individually.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/244,454 entitled “Compression in Communications”filed Oct. 21, 2015, the entire content of which is incorporated hereinby reference.

FIELD OF THE INVENTION

The invention relates generally to communications and more particularlyto apparatus and methods for compressing and decompressing traffic unitsin communication traffic.

BACKGROUND

Nodes/devices in a communication network exchange information betweeneach other. This information may include segments or units of traffic,such as packets, which may include overhead information and payloadinformation. Overhead information may include header information, forexample, that may be useful in routing a packet through the network,identifying the content in the packet, processing the packet, etc.Payload information could include user data, multimedia content, etc. ina payload portion of the packet.

SUMMARY

According to one aspect of the present invention, there is provided amethod of processing communication traffic comprising a plurality oftraffic units, each traffic unit having a header and a payload, themethod comprising: selectively applying header compression to headers oftraffic units from the communication traffic; selectively applyingbit-level bulk data compression to the communication traffic, whereinbit-level bulk data compression comprises accumulating blocks of bits,including headers and payloads of traffic units from the communicationtraffic, and operating on each block individually.

In some embodiments, the communication traffic comprises a plurality oftraffic flows, each traffic flow comprising a plurality of trafficunits, and selectively applying header compression to headers of trafficunits from the communication traffic comprises selectively applyingheader compression to headers of traffic units from the plurality oftraffic flows on a flow-by-flow basis.

In some embodiments, the method further comprises: identifying a trafficflow type for each traffic flow of the plurality of traffic flows,wherein selectively applying header compression to headers of trafficunits from the plurality of traffic flows on a flow-by-flow basiscomprises, for each traffic flow, selectively applying headercompression to headers of traffic units from the traffic flow depending,at least in part, on the traffic flow type identified for the trafficflow.

In some embodiments, the communication traffic comprises a plurality oftraffic flows, each traffic flow comprising a plurality of trafficunits, and selectively applying bit-level bulk data compression to thecommunication traffic comprises selectively applying bit-level bulk datacompression to the plurality of traffic flows on a flow-by-flow basis.

In some embodiments, the method further comprises: identifying a trafficflow type for each traffic flow of the plurality of traffic flows,wherein selectively applying bit-level bulk data compression to theplurality of traffic flows on a flow-by-flow basis comprises, for eachtraffic flow, selectively applying bit-level bulk data compression tothe traffic flow depending, at least in part, on the traffic flow typeidentified for the traffic flow.

In some embodiments, the method further comprises receiving thecommunication traffic from a plurality of traffic queues, whereinselectively applying header compression to headers of traffic units fromthe communication traffic comprises selectively applying headercompression to headers of traffic units from the communication trafficon a queue-by-queue basis.

In some embodiments, the method further comprises receiving thecommunication traffic from a plurality of traffic queues, whereinselectively applying bit-level bulk data compression to thecommunication traffic comprises selectively applying bit-level bulk datacompression to the communication traffic on a queue-by-queue basis.

In some embodiments, the bit-level bulk data compression is lossless.

In some embodiments, a size of the blocks upon which the bit-level bulkdata compression operates is user selectable.

According to another aspect of the present invention, there is provideda non-transitory computer-readable medium storing instructions which,when executed, perform the method according to the above aspect of thepresent invention.

According to yet another aspect of the present invention, there isprovided an apparatus for processing communication traffic comprising aplurality of traffic units, each traffic unit having a header and apayload, the apparatus comprising: a header compressor to selectivelyapply compression to headers of traffic units from the communicationtraffic; a bit-level bulk data compressor, operatively coupled to anoutput of the header compressor, to selectively apply bit-level bulkdata compression to the communication traffic, wherein bit-level bulkdata compression accumulates blocks of bits, including headers andpayloads of traffic units from the communication traffic, and operateson each block individually.

In some embodiments: the communication traffic comprises a plurality oftraffic flows, each traffic flow comprising a plurality of trafficunits; and the header compressor is configured to selectively applyheader compression to headers of traffic units from the plurality oftraffic flows on a flow-by-flow basis.

In some embodiments, for each traffic flow of the plurality of trafficflows, the header compressor is configured to selectively apply headercompression to headers of traffic units from the traffic flow depending,at least in part, on a traffic flow type identified for the trafficflow.

In some embodiments: the communication traffic comprises a plurality oftraffic flows, each traffic flow comprising a plurality of trafficunits; and the bit-level bulk data compressor is configured toselectively apply bit-level bulk data compression to the plurality oftraffic flows on a flow-by-flow basis.

In some embodiments, for each traffic flow of the plurality of trafficflows, the bit-level bulk data compressor is configured to selectivelyapply bit-level bulk data compression to the traffic flow depending, atleast in part, on a traffic flow type identified for the traffic flow.

In some embodiments: the communication traffic is received from aplurality of traffic queues; and the header compressor is configured toselectively apply header compression to headers of traffic units fromthe communication traffic on a queue-by-queue basis.

In some embodiments: the communication traffic is received from aplurality of traffic queues; and the bit-level bulk data compressor isconfigured to selectively apply bit-level bulk data compression to thecommunication traffic on a queue-by-queue basis.

In some embodiments, the bit-level bulk data compressor is configured toinstantiate a plurality of bit-level bulk data compressor instances,each bit-level bulk data compressor instance being individuallyconfigurable to selectively apply bit-level bulk data compression to thecommunication traffic by accumulating blocks of bits from at least oneof the traffic queues, and operating on each block individually.

In some embodiments, the bit-level bulk data compression selectivelyapplied by the bit-level bulk data compressor is lossless.

In some embodiments, the size of the blocks upon which the bit-levelbulk data compressor operates is user selectable.

According to still another aspect of the present invention, there isprovided a method of processing communication traffic comprising aplurality of traffic units, each traffic unit having a header and apayload, the method comprising: selectively applying bit-level bulk datadecompression to the communication traffic, wherein bit-level bulk datadecompression comprises accumulating blocks of bits, including headersand payloads of traffic units from the communication traffic, andoperating on each block individually; selectively applying headerdecompression to headers of traffic units from the communicationtraffic.

In some embodiments, the method further comprises receiving bit-levelbulk data decompression information in respect of the communicationtraffic, wherein the bit-level bulk data decompression information inrespect of the communication traffic is used when selectively applyingbit-level bulk data decompression to the communication traffic.

According to a further aspect of the present invention, there isprovided a non-transitory computer-readable medium storing instructionswhich, when executed, perform the method according to the above aspectof the present invention.

According to still another aspect of the present invention, there isprovided an apparatus for processing communication traffic comprising aplurality of traffic units, each traffic unit having a header and apayload, the apparatus comprising: a bit-level bulk data decompressor toselectively apply bit-level bulk data decompression to the communicationtraffic, wherein bit-level bulk data decompression accumulates blocks ofbits, including headers and payloads of traffic units from thecommunication traffic, and operates on each block individually; a headerdecompressor, operatively coupled to an output of the bit-level bulkdata decompressor, to selectively apply header decompression to headersof traffic units from the communication traffic.

In some embodiments, the bit-level bulk data decompressor is configuredto receive bit-level bulk data decompression information in respect ofthe communication traffic and use the bit-level bulk data decompressioninformation when selectively applying bit-level bulk data decompressionto the communication traffic.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of embodiments of the invention will now be described ingreater detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of an example packet flow.

FIG. 2 is a block diagram of an example communication system.

FIG. 3 is a block diagram of an example apparatus for compressingcommunication traffic.

FIG. 4 is a block diagram of an example apparatus for decompressingcommunication traffic.

FIG. 5 is a flow diagram of an example method.

FIG. 6 is a flow diagram of another example method.

DETAILED DESCRIPTION

Generally, embodiments of the present invention provide apparatus andmethods for compressing and decompressing traffic units in communicationtraffic. For simplicity and clarity of illustration, reference numeralsmay be repeated among the figures to indicate corresponding or analogouselements. Numerous details are set forth to provide an understanding ofthe examples described herein. The examples may be practiced withoutthese details. In other instances, well-known methods, procedures, andcomponents are not described in detail to avoid obscuring the examplesdescribed. The description is not to be considered as limited to thescope of the examples described herein.

In many forms of communication, and particularly in wirelesscommunication, bandwidth resources for transmission of communicationtraffic is often limited. In many communication systems, information iscommunicated in units of traffic, such as packets or frames, that eachinclude some overhead information, in the form of a header, and apayload that carries at least some portion of information. These unitsare generally referred to herein as traffic units.

A sequence of traffic units from a source to a destination (unicast), orto multiple destinations (multicast or broadcast), may be considered atraffic flow. For example, in a packet switched network, a sequence ofpackets from a source to one or more destinations may be considered apacket flow. FIG. 1 is a block diagram of an example packet flow 10 thatdepicts M packets (packet N to packet N+M) in the flow. As shown in FIG.1, each packet in the flow includes a header and a payload, such thatpacket N includes a header 12 _(N) and a payload 14 _(N), and packet N+Mincludes a header 12 _(N+M) and a payload 14 _(N+M). The traffic units(packets in this example) in a traffic flow (packet flow in thisexample) often share similar headers, which means that in a traffic flowthere is often at least a portion of a header that is repeated acrossmultiple traffic units.

In some cases, the header (i.e. overhead information) may occupy arelatively large portion of a traffic unit. For example, in short packetflows, the packet header may occupy a relatively large portion of apacket. Accordingly, transmission of information in such traffic unitsmay be relatively inefficient because much of the bandwidth fortransmitting information may be used to transmit header information asopposed to the actual payload information.

In some communication systems, the header portion of traffic units maybe compressed prior to transmission in order to reduce the amount ofoverhead information that is transmitted. This type of compression isreferred to as header compression, because it operates on overheadinformation in the header portion of a traffic unit.

Header compression can potentially provide a substantial improvement inefficiency for communication traffic that includes traffic units inwhich the header occupies a relatively large portion of each trafficunit and the traffic is repetitive in the sense that many of the trafficunits share a common header or at least portions of the headers indifferent traffic units are common. For example, in some cases headercompression has been shown to be well suited to low data rate Voice overInternet Protocol (VoIP) communications.

In contrast, compression schemes that compress the payload portion of atraffic unit often yield better results, in terms of higher compressiongain, for communication traffic that includes traffic units in which thepayload occupies a relatively large portion of each traffic unit. Apacket flow for a File Transfer Protocol/Transmission Control Protocol(FTP/TCP) communication may generate such communication traffic.

Bit-level bulk data compression operates by accumulating blocks of datafrom communication traffic, including headers and payloads from multipletraffic units in the communication traffic, and operating on each blockindividually. This type of compression is generally suited forcompressing blocks of data in communication traffic with embeddedrepetitive patterns.

However, such bit-level bulk data compression may not provide acceptablecompression results for low data rate communication traffic withrandomized or generally less repetitive data, because the bulkcompression process operates on a block of data (e.g., 8000 bytes) at atime and performs compression on the block. For some types of trafficflows that are low data rate in nature, such as low data rate VoIPpacket flows, the traffic units associated with the flows are spacedsuch that there are not multiples of the same flow in a bulk compressedblock. This means that even though a traffic flow may include repetitivecontent, such as in the header portions of its traffic units, thisrepetitive pattern may not be exploited by bit-level bulk datacompression that operates on blocks of data individually.

Performing bit-level bulk data compression on larger blocks and/oracross multiple blocks in order to potentially exploit the repetitivecontent of some low data rate traffic flows that may be missed in asingle smaller block of data is often not feasible. For example, thereis an additional delay penalty associated with processing across largerblocks or across multiple blocks, as it takes longer to accumulate andprocess the data block or blocks for compression.

Aspects of the present invention provide methods and apparatus thatcombine selective application of header compression with selectiveapplication of bit-level bulk data compression for communication trafficprocessing.

This combination can potentially be advantageous, for example, fortraffic flow types that may not compress well in bulk compression, dueto having a low data rate for example, but have compressible overheadinformation that can be compressed by applying header compression to thetraffic flow instead of, or prior to, bulk compression.

Bulk data compression operates on blocks of data. Therefore the delayassociated with accumulating a block of data means that bulk datacompression is a non-real time form of compression. The delay that maybe incurred accumulating a block of traffic to be compressed may be atleast partially offset by an acceleration in transmitting the compressedtraffic, because the compressed version of the block is of a reducedsize, meaning that less data has to be sent and therefore canpotentially be sent in less time. However, some communication trafficmay be particularly sensitive to delay. For such traffic, it may bepreferable to not apply bulk data compression to the traffic, even ifthe delay associated with bulk data compression is at least partiallymitigated by the potentially reduced data size due to the compression.

FIG. 2 is a block diagram of an example communication system 100.Communication system 100 includes a first wireless communication device106, a second wireless communication device 108, a first communicationnetwork 102, and a second communication network 104. First wirelesscommunication device 106 is communicatively coupled to network 102through a communication link 105 and second wireless communicationdevice 108 is communicatively coupled to communication network 104through a communication link 107.

In one embodiment, the communication networks 102 and 104 are Ethernetnetworks.

The communication link 105 between wireless communication device 106 andcommunication network 102, and the communication link 107 betweenwireless communication device 108 and communication network 104, may bewired communication links, wireless communication links, or somecombination thereof.

The communications circuitry used to implement wireless communicationdevices 106 and 108 is implementation-dependent. In general, hardware,firmware, components which execute software, or some combinationthereof, might be used in implementing such communications circuitry.Electronic devices that might be suitable for implementingcommunications circuitry include, among others, microprocessors,microcontrollers, Programmable Logic Devices (PLDs), Field ProgrammableGate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs),and other types of “intelligent” integrated circuits. Software could bestored in memory for execution. The memory could include one or morephysical memory devices, including any of various types of solid-statememory devices and/or memory devices with movable or even removablestorage media.

Although the communication system 100 depicted in FIG. 2 includes onlytwo communication networks 102 and 104, each having only one wirelesscommunication device communicatively coupled thereto, more generally acommunication system may include any number of communication networks,each having any number of wireless communication devices respectivelycoupled thereto. Furthermore, in some embodiments wireless communicationdevices, such as wireless communication devices 106 and 108, may beconfigured to transmit wireless signals to and/or receive wirelesscommunication signals from multiple other wireless communicationdevices. In some embodiments, wireless communication devicescommunicatively coupled to the same communication network maycommunicate wirelessly with one another. In one specific embodiment,wireless communication devices and communication networks are arrangedto provide an Ethernet mesh/ring network.

Wireless communication device 106 receives communication traffic (e.g.,in the form of data packets) that is routed through communicationnetwork 102, generates wireless communication signals based on thecommunication traffic, and transmits the wireless communication signalsto wireless communication device 108. Wireless communication device 108receives wireless communication signals from wireless communicationdevice 106, generates communication traffic based on the wirelesscommunication signals, and sends the generated communication traffic toone or more nodes in communication network 104. Similarly, wirelesscommunication devices 106 and 108 may be configured so thatcommunication traffic routed through communication network 104 andreceived at wireless communication device 108 can be wirelesslytransmitted to and received by wireless communication device 106 to berouted to one or more nodes in communication network 102.

A portion of an example communication traffic processing chain 110 forwireless communication device 106 is also shown in FIG. 2. The examplecommunication traffic processing chain 110 includes a switching andpolicing module 112, a compressor 114, a modem 116 and a radio frequency(RF) transmit/receive device 118. The switching and policing module 112is operatively coupled to the compressor 114, which is in turnoperatively coupled to the modem 116, which is in turn operativelycoupled to the RF transmit/receive device 118. The switching andpolicing module 112, the compressor 114, the modem 116 and the RFtransmit/receive device 118 could be implemented in hardware, firmware,one or more components, such as a processor, that execute software, orcombinations thereof.

In operation, the switching and policing module 112 performs a switchingand policing function on communication traffic that includes trafficunits such as packets, that each have a header and a payload. In someembodiments, the switching and policing function performed by theswitching and policing module 112 includes sorting traffic units into aplurality of traffic queues in one or more memory devices (not shown inFIG. 2) based, for example, on traffic type. For example, in someembodiments the switching and policing module 112 sorts each packet flowof multiple packet flows into one of multiple traffic queues based on atraffic type identified for the packet flow. In such embodiments, packetflows of a first traffic type, illustratively VoIP traffic, may besorted into a first traffic queue, while packet flows of a secondtraffic type, such as FTP/TCP, may be sorted into a second trafficqueue.

Compressor 114 receives communication traffic that has been processed bythe switching and policing module 112 and further processes thecommunication traffic by selectively applying header compression toheaders of traffic units from the communication traffic, and selectivelyapplying bit-level bulk data compression to the communication traffic.The bit-level bulk data compression accumulates blocks of bits,including headers and payloads of traffic units from the communicationtraffic, and operates on each block individually. In some embodiments,the size of the blocks upon which the bit-level bulk data compressionoperates is user selectable.

In some embodiments, the communication traffic includes multiple trafficflows, and each traffic flow includes multiple traffic units. In suchembodiments, the compressor 114 may be configured to selectively applyheader compression and/or bit-level bulk data compression to thecommunication traffic on a flow-by-flow basis. In some cases, a trafficflow type may be identified for each traffic flow, and the compressor114 may selectively apply header compression and/or bit-level bulk datacompression to a traffic flow based, at least in part, on the trafficflow type associated with the traffic flow.

Table 1 below illustrates the complementary nature of header compressionand bit-level bulk data compression for various types of communicationtraffic, showing the potential benefit that may be realized byselectively combining header compression and bit-level bulk datacompression.

TABLE 1 Compression Compression Efficiency Efficiency for Header forBulk Data Traffic Type Compression Compression Low data rate, short HighLow traffic unit flows (e.g., VoIP) High data rate, short Medium-HighLow-Medium traffic unit flows (e.g., VidoIP, TDMoE) Low data rate, longtraffic Low High unit flows (e.g., FTP/TCP) High data rate, long LowHigh traffic unit flows (e.g., FTP/TCP) Encrypted flows High Low

As illustrated in Table 1, header compression can provide gains on shorttraffic unit flows with traffic units that are relatively short, so thatthe header occupies a significant portion of the size of each trafficunit. On the other hand, bulk data compression can provide gains onblocks of data from long traffic unit flows with bit-level sequences,including headers and payloads of traffic units, that exhibitcompressible sequences or patterns.

Selectively applying the header compression and bulk data compression ona flow-by-flow basis, for example, potentially allows header compressionand/or bulk data compression to be applied to those flows that maybenefit from one compression scheme or the other, or both, whilebypassing header compression and/or bulk data compression for otherflows. For example, some traffic flows may be particularly sensitive toany delay, and therefore for such flows it may be preferable to bypassbulk data compression.

Traffic flow type is only one example of a criterion upon which theselective application of header compression and/or bit-level bulk datacompression may be based. One or more other criteria could potentiallybe used in addition to or instead of traffic flow type in otherembodiments.

In some embodiments, the compressor 114 may be configured to selectivelyapply header compression and/or bulk data compression based on theswitching and policing configuration determined by switching andpolicing module 112. For example, the switching and policing module 112may sort communication traffic into traffic queues, and the compressor114 may be configured to selectively apply header compression and/orbulk data compression on a queue-by-queue basis.

Further details of compressor 114 and an example implementation arediscussed later with reference to FIG. 3.

Modem 116 and RF transmit/receive device 118 function as an RF front endfor wireless communication device 106. Modem 116 modulates the processedcommunication traffic from compressor 114 to generate signals suitablefor wireless transmission, which RF Tx/Rx 118 then uses to generatewireless communication signals to transmit the processed communicationtraffic.

Details of the communication circuitry of wireless communication device108 are not shown in FIG. 2, but in one embodiment they include an RFfront end configured to receive wireless communication signals anddemodulate the wireless communication signals to generate communicationtraffic, and a decompressor configured to selectively apply bit-levelbulk data decompression to the communication traffic, and thenselectively apply header decompression to headers of traffic units fromthe communication traffic. As with the bit-level bulk data compression,the bit-level bulk data decompression involves accumulating blocks ofbits from the communication traffic, and operating on each blockindividually. Further details of a decompressor and an exampleimplementation are discussed later with reference to FIG. 4.

It should also be appreciated that both a compression/transmitcommunication traffic processing chain such as 110 and adecompression/receive communication traffic processing chain could beimplemented in a single communication device. In many implementations,communication devices or equipment support transmit and receivecapabilities and therefore a single device or equipment installationcould include compression/transmit and receive/decompression circuitry.

Referring now to FIG. 3, which is a block diagram of an exampleapparatus for implementing compressor 114, the compressor 114 includes amultiplexer 204, which is operatively coupled to a header compressor200, which in turn is operatively coupled to a bit-level bulk datacompressor 202, which in turn is operatively coupled to a demultiplexer206. The multiplexer 204, header compressor 200, bit-level bulk datacompressor 202, and demultiplexer 206 could be implemented in hardware,firmware, one or more components, such as a processor, that executesoftware, or combinations thereof.

In operation, multiplexer 204 receives communication traffic from one ormore traffic queues, for example, and multiplexes the communicationtraffic into a stream of traffic units for processing by headercompressor 200.

Header compressor 200 selectively applies header compression to thecommunication traffic received from multiplexer 204 and passes theresulting communication traffic to bit-level bulk data compressor 202.The selective application of header compression by header compressor 200is depicted by way of a dashed-line bypass path through headercompressor 200. This is intended to indicate that header compressor 200may be configured such that it may apply header compression to somecommunication traffic, while not applying header compression to othercommunication traffic.

In some embodiments, header compressor 200 is configurable toselectively apply header compression by selectively operating in eitheran “on” state or an “off” state. In such embodiments, when in the “on”state, header compressor 200 applies header compression to allcommunication traffic, whereas when in the “off” state, it does notapply header compression to any communication traffic.

The communication traffic received by the header compressor 200 mayinclude multiple traffic flows that each include multiple traffic units.In some cases, header compressor 200 may be configured to selectivelyapply header compression to headers of traffic units from the trafficflows on a flow-by-flow basis. For example, header compressor 200 mayapply header compression to headers of communication traffic units fromone traffic flow, while not applying header compression to headers ofcommunication traffic units from another traffic flow.

In some embodiments, header compressor 200 is configured such that, foreach of the multiple traffic flows, it selectively applies headercompression to headers of traffic units from the traffic flow depending,at least in part, on a traffic flow type identified for the trafficflow. For example, header compressor 200 may be configured to applyheader compression to traffic flow(s) identified as being of a firsttraffic flow type, such as VoIP, VidoIP (Video over IP) or TDMoE (TimeDivision Multiplexing over Ethernet), and configured to not apply headercompression to traffic flow(s) identified as being of a second trafficflow type, such as FTP/TCP.

In the example apparatus shown in FIG. 3, the multiplexer 204 receivesthe communication traffic from one or more traffic queues. In someembodiments, header compressor 200 is configured to selectively applyheader compression to headers of traffic units from the communicationtraffic on a queue-by-queue basis. In some cases, the communicationtraffic may have been sorted into traffic queues based on one or morecriteria, such as priority, desired data rate, and/or traffic flow type.

In one embodiment, the header compression applied by header compressor200 is based on a modified version of the IP header compressiontechnique described in “IP header compression” RFC 2507, InternetEngineering Task Force (1999) by S. Pink, M. Degermark, and B. Nordgren.

In one example embodiment, header compressor 200 monitors communicationtraffic to identify traffic unit flows, and builds a watched list storedin memory (not shown) of traffic flows that it has identified. In oneparticular embodiment the watched list may include approximately 4000 ofthe most recent traffic unit flows that header compressor 200 hasidentified. The specific size of the watched list may be different indifferent embodiments. For example, in some embodiments it may be largerthan 4000, and in other embodiments it may be smaller.

From the watched list, header compressor 200 may extract a smaller mostcommonly seen list that includes, for example approximately 1000 of themost commonly recurring traffic flows in the watched list. In anembodiment, each time a new entry is made in the most commonly seenlist, a traffic unit belonging to the traffic flow corresponding to thenew entry is transmitted to the far-end of the communication linkcorresponding to the traffic flow together with a compressioncontext-identification (CID). In FIG. 2, for example, the far-end withrespect to wireless communication device 106 is wireless communicationdevice 108. Subsequent traffic units with header information matching anentry on the most commonly seen list have their matching headerinformation replaced with the CID corresponding to their matching entrybefore being transmitted to the far-end. An entire header or a portionof the header could be replaced, depending on the extent of the match.At the far-end, the original header information is substituted for theCIDs in a header decompression process. In some embodiments, an errorcheck may then be carried out, such as a cyclic redundancy check (CRC).Errored traffic units may be discarded, while non-errored traffic unitsmay be forwarded for further processing.

According to the above embodiment, when a given traffic flow stops orslows, and thus begins to recur less often in the watched list, itnaturally gets removed from the most commonly seen list, as othertraffic flows begin to recur more regularly in the watched list.

In one example embodiment, header compressor 200 selectively appliesheader compression to headers of traffic units by initially classifyingeach traffic unit into one of multiple traffic unit header types. Forexample, in one such embodiment each traffic unit may be classified intoone of four possible header types: uncompressible, compressible non-IP,compressible non-TCP and compressible TCP. In some such embodiments, theheader compression applied to a traffic unit is in accordance with theheader type classification for the traffic unit. In some cases, headercompression is executed in layers, meaning that header compression mayoperate on a portion of a header, while leaving one or more otherportions of the header uncompressed. By operating in this manner, insome cases even “exotic” headers that may include one or more portionsthat may not be compressible with a particular header compressionalgorithm, may be at least partially compressed. Header compressioncould operate on only the portion(s) of such a header that may becompressible by the header compression algorithm, while not operating onthe portion(s) that may not be compressible by the header compressionalgorithm.

In many cases, header compression can be performed in real time ornear-real time operation, and thus causes little to no delay. Headercompression is lossless, meaning that compressed headers can bedecompressed without any loss of information. It may also be possible toimplement header compression so that it is non-expanding.

In some embodiments, information pertaining to headercompression/decompression, such as tables mapping CIDs to headerinformation, and tables for the most commonly seen list and the watchedlist, may be stored in a manner that allows the information to survivethrough power outages and/or radio link outages. For example, in someembodiments such information may be stored in non-volatile memory. Insome cases this may allow header compression/decompression to resumeimmediately once power and/or a radio link is restored/resumed, assumingthat the traffic unit flows upon which the information is based have notbecome stale and the information is still relevant to active trafficunit flows.

It is to be understood that the particular examples of headercompression discussed above are merely examples provided forillustrative purposes only. More generally, other forms of headercompression are contemplated.

Bit-level bulk data compressor 202 selectively applies bit-level bulkdata compression to the communication traffic by accumulating blocks ofbits, including headers and payloads of traffic units from thecommunication traffic, and operates on each block individually. Theheaders could be in their original form as received by the multiplexer204, or in a compressed form if header compression was applied by theheader compressor 200. Similar to the depiction of the selectiveapplication of header compression by header compressor 200, theselective application of bit-level bulk data compression by bit-levelbulk data compressor 202 is depicted by way of a dashed-line bypass paththrough bit-level bulk data compressor 202. This is intended to indicatethat bit-level bulk data compressor 202 may be configured such that itmay apply bit-level bulk data compression to some communication traffic,while not applying bit-level bulk data compression to othercommunication traffic.

In some embodiments, the size of the blocks upon which the bit-levelbulk data compressor 202 operates is user selectable. For example, inone particular embodiment, a user may select from block sizes thatinclude 256, 512, 1024, 4000 or 8000 bytes. Larger blocks may compressmore efficiently, but may come at the expense of an increased delayassociated with the time to accumulate and/or process a larger block.

As noted above, in many cases communication traffic may include multipletraffic flows. In some embodiments, bit-level bulk data compressor 202is configured to selectively apply bit-level bulk data compression tomultiple traffic flows on a flow-by-flow basis. For example, bit-levelbulk data compressor 202 may be configured to apply bit-level bulk datacompression to traffic flow(s) identified as being of a first trafficflow type, such as FTP/TCP, and configured to not apply bit-level bulkdata compression to traffic flow(s) identified as being of a secondtraffic flow type, such as VoIP, VidoIP or TDMoE.

Also as noted above, in some embodiments the multiplexer 204 may receivethe communication traffic from one or more traffic queues. In some suchembodiments, bit-level bulk data compressor 202 may be configured toselectively apply bit-level bulk data compression to the communicationtraffic on a queue-by-queue basis. For example, bit-level bulk datacompressor 202 may be configured to accumulate blocks of bits from sometraffic queues, and operate on those accumulated blocks individually,while traffic units from other traffic queues are allowed to passwithout bit-level bulk data compression.

In some embodiments, bit-level bulk data compressor 202 is configured toinstantiate multiple bit-level bulk data compressor instances 202 ₁, 202₂, 202 ₃, . . . , 202 _(N). Each bit-level bulk data compressor instancecould be individually configurable to selectively apply bit-level bulkdata compression to the communication traffic by accumulating blocks ofbits from at least one of the traffic queues, and operate on each blockindividually. For example, one or more of the bit-level bulk datacompressor instances 202 ₁, 202 ₂, 202 ₃, . . . , 202 _(N) may bemultiplexed onto a single traffic queue or multiple traffic queues toselectively apply bit-level bulk data compression to communicationtraffic from the queue(s).

In one particular embodiment, each bit-level bulk data compressorinstance can process 1 Gbps throughput. In other embodiments thethroughput may be higher or lower.

In one embodiment, the bit-level bulk data compression applied bybit-level bulk data compressor 202 is based on a modified version of alossless Lempel Ziv-Ross Williams (LZRW) compression algorithm, whichitself is a modified version of a lossless Lempel Ziv (LZ) compressionalgorithm. However, it should be appreciated that other losslessbit-level bulk data compression techniques may be used in otherembodiments. LZ based bulk data compression may be preferred in somecases because it can be implemented without relying on tables. This typeof bulk data compression can instead be implemented so that it iscompletely dynamic, meaning that each compressed block is independentlydecompressible on its own and each compressed block is accompanied bydecompression information that allows a bulk data decompressor at thefar-end to decompress it. This also means that there is potentially noimpact to bulk data compression when there are power outages or radiolink outages, and therefore compression/decompression potentially resumeoperation once power or a radio link is restored.

As with the header compression applied by header compressor 200, thebit-level bulk data compression applied by bit-level bulk datacompressor 202 is lossless and can be implemented so that it isnon-expanding. For example, in an embodiment, if any expansion isdetected, the uncompressed block is transmitted instead of the expandedblock. In some embodiments, the check for expansion is implemented in atransparent, non-performance impacting process that happens in realtime.

Demultiplexer 206 demultiplexes the output of bulk data compressor 202and passes the demultiplexed output to an RF front end for transmission.

The compression gain performance that may be provided by combiningheader compression and bit-level bulk data compression as disclosedherein can be affected by numerous factors associated with thecommunication traffic that is to be processed, including, but notlimited to:

-   -   the mixture of traffic unit sizes;    -   the number of traffic flows;    -   the type of traffic units (TCP or User Datagram Protocol (UDP),        IPV4 or IPV6, Multiprotocol Label Switching (MPLS), General        Packet Radio Service Tunnelling Protocol (GTP), etc.); and    -   contents within the payload fields of the traffic units.

Generally, the combination of header compression and bit-level bulk datacompression as described herein might not appreciably alter latencyperformance of a wireless communication link. In some cases, for smallerpacket sizes, for example, the delay may be roughly equivalent to thedelay without compression (+/−10 μs compression on or off). In othercases there may be an improvement in delay, for larger packets with goodcompressibility, for example.

Table 2 below shows some test results for one-way latency over awireless communication link with and without compression as describedherein for two different packet sizes tested on a 28 MHz bandwidth, 2048Quadrature Amplitude Modulation (QAM), pseudorandom binary sequence(PRBS9) test pattern. It is to be understood that these test results areonly representative of one very specific embodiment in one very specifictesting scenario, and the same or different results may be obtained withother embodiments and/or other testing scenarios. As shown in the table,the latency with compression for the smaller packet size (1518 bytepackets) is only marginally higher than that without compression, andthe latency with compression for the larger packet size (9600 bytepackets) is less than the latency without compression.

TABLE 2 Latency without Latency with Compression Compression Packet Size(one-way, typical) (one-way, typical) 1518 bytes 256 μs 257.2 μs 9600bytes 618 μs   486 μs

FIG. 4 is a block diagram of an example apparatus 300 for decompressingcommunication traffic. Such an apparatus may be employed, for example,as part of a decompressor in the communication circuitry of wirelesscommunication device 108 to decompress compressed communication trafficreceived from wireless communication device 106. The example apparatus300 shown in FIG. 4 includes a bit-level bulk data decompressor 302,which is operatively coupled to a header decompressor 304. The bit-levelbulk data decompressor 302 and the header decompressor 304 could beimplemented in hardware, firmware, one or more components, such as aprocessor, that execute software, or combinations thereof.

In operation, bit-level bulk data decompressor 302 receivescommunication traffic from an RF front end. The RF front end could beimplemented as shown in FIG. 2 for the wireless communication device 106with a transmit/receive device and a modem, for example. Thecommunication traffic may or may not have been compressed with headercompression and/or bit-level bulk data compression before beingtransmitted over a wireless communication link. Bit-level bulk datadecompressor 302 selectively applies bit-level bulk data decompressionto the communication traffic. The bit-level bulk data decompressor 302accumulates blocks of bits, including headers and payloads of trafficunits from the communication traffic, and operates on each blockindividually. Bit-level bulk data decompressor 302 then passes theresulting communication traffic to header decompressor 304. Headerdecompressor 304 then selectively applies header decompression toheaders of traffic units from the communication traffic. The selectiveapplication of decompression by bit-level bulk data decompressor 302 andheader decompressor 304 are depicted by way of dashed-line bypass pathsto indicate that the decompressors may be configured to applydecompression to some communication traffic, while not applying it toother communication traffic.

In some embodiments, bit-level bulk data decompressor 302 receivesbit-level bulk data decompression information in respect of thecommunication traffic and uses the bit-level bulk data decompressioninformation when selectively applying bit-level bulk data decompressionto the communication traffic. In some embodiments, the bit-level bulkdata decompression information accompanies the communication trafficwhen it is transmitted over a wireless communication link.

In some embodiment, header decompression involves comparing a CIDretrieved from a traffic unit to a mapping of CIDs to headerinformation, and replacing the CID with corresponding header informationif a match is found.

FIG. 5 is a flow diagram of an example method. The example method 400relates to processing communication traffic that includes a plurality oftraffic units, each traffic unit having a header and a payload. Theexample method 400 includes selectively applying header compression toheaders of traffic units from the communication traffic, at 402.Bit-level bulk data compression is selectively applied to thecommunication traffic at 404. The bit-level bulk data compressionselectively applied at 404 involves accumulating blocks of bits,including headers and payloads of traffic units from the communicationtraffic, and operating on each block individually.

The example method 400 is illustrative of one embodiment. In otherembodiments, similar or different operations could be performed in asimilar or different order. Various ways to perform the illustratedoperations, as well as examples of other operations that may beperformed, are described herein. Further variations may be or becomeapparent.

FIG. 6 is a flow diagram of another example method. The example method500 also relates to processing communication traffic that includes aplurality of traffic units, each traffic unit having a header and apayload. The example method 500 includes selectively applying bit-levelbulk data decompression to the communication traffic at 502. Thebit-level bulk data decompression selectively applied at 502 involvesaccumulating blocks of bits, including headers and payloads of trafficunits from the communication traffic, and operating on each blockindividually. Header decompression is selectively applied to headers oftraffic units from the communication traffic at 504.

The example method 500 is illustrative of one embodiment. In otherembodiments, similar or different operations could be performed in asimilar or different order. Various ways to perform the illustratedoperations, as well as examples of other operations that may beperformed, are described herein. Further variations may be or becomeapparent.

What has been described is merely illustrative of the application ofprinciples of embodiments of the present disclosure. Other arrangementsand methods can be implemented by those skilled in the art.

For example, while the foregoing description refers to radio signals,the radio signals instead may be microwave signals. Embodiments of theinvention are not limited to transmitting any particular type of signal,whether radio wave, microwave, or other types of signalling.

Similarly, while the above description refers to various examples ofheader compression techniques and bit-level bulk data compressiontechniques, embodiments of the invention are not limited to anyparticular header compression technique or any particular bit-level bulkdata compression technique. Other lossless header and bit-level bulkdata compression techniques may be used to compress data before it istransmitted to a receiver.

Furthermore, it should be appreciated that the compression techniquesdescribed herein are not limited to use in conjunction with anyparticular communication protocol. As such, although some of thecompression techniques described herein are discussed in conjunctionwith TCP/IP and Ethernet protocols, more generally embodiments can beused in conjunction with any set of communication protocols. Similarly,while some embodiments may exploit knowledge of the type of traffic thatis to be processed, in other embodiments the compression techniquesdisclosed herein may be used without any knowledge or assumption as tothe type of traffic.

In the preceding description, for purposes of explanation, numerousdetails are set forth in order to provide a thorough understanding ofthe embodiments. However, it will be apparent to one skilled in the artthat these specific details are not required. In other instances,well-known electrical structures and circuits are shown in block diagramform in order not to obscure the understanding. For example, specificdetails are not provided as to whether the embodiments described hereinare implemented as a software routine, hardware circuit, firmware, or acombination thereof.

Embodiments of the disclosure can be represented as a computer programproduct stored in a machine-readable medium (also referred to as acomputer-readable medium, a processor-readable medium, or a computerusable medium having a computer-readable program code embodied therein).The machine-readable medium can be any suitable tangible, non-transitorymedium, including magnetic, optical, or electrical storage mediumincluding a diskette, compact disk read only memory (CD-ROM), memorydevice (volatile or non-volatile), or similar storage mechanism. Themachine-readable medium can contain various sets of instructions, codesequences, configuration information, or other data, which, whenexecuted, cause a processor to perform steps in a method according to anembodiment of the disclosure. Those of ordinary skill in the art willappreciate that other instructions and operations necessary to implementthe described implementations can also be stored on the machine-readablemedium. The instructions stored on the machine-readable medium can beexecuted by a processor or other suitable processing device, and caninterface with circuitry to perform the described tasks.

The above-described embodiments are intended to be examples only.Alterations, modifications and variations can be effected to theparticular embodiments by those of skill in the art. The scope of theclaims should not be limited by the particular embodiments set forthherein, but should be construed in a manner consistent with thespecification as a whole.

1. A method of processing communication traffic comprising a pluralityof traffic units, each traffic unit having a header and a payload, themethod comprising: selectively applying header compression to headers oftraffic units from the communication traffic; selectively applyingbit-level bulk data compression to the communication traffic, whereinbit-level bulk data compression comprises accumulating blocks of bits,including headers and payloads of traffic units from the communicationtraffic, and operating on each block individually.
 2. The method ofclaim 1, wherein the communication traffic comprises a plurality oftraffic flows, each traffic flow comprising a plurality of trafficunits, and selectively applying header compression to headers of trafficunits from the communication traffic comprises selectively applyingheader compression to headers of traffic units from the plurality oftraffic flows on a flow-by-flow basis.
 3. The method of claim 3, furthercomprising: identifying a traffic flow type for each traffic flow of theplurality of traffic flows, wherein selectively applying headercompression to headers of traffic units from the plurality of trafficflows on a flow-by-flow basis comprises, for each traffic flow,selectively applying header compression to headers of traffic units fromthe traffic flow depending, at least in part, on the traffic flow typeidentified for the traffic flow.
 4. The method of claim 1, wherein thecommunication traffic comprises a plurality of traffic flows, eachtraffic flow comprising a plurality of traffic units, and selectivelyapplying bit-level bulk data compression to the communication trafficcomprises selectively applying bit-level bulk data compression to theplurality of traffic flows on a flow-by-flow basis.
 5. The method ofclaim 4, further comprising: identifying a traffic flow type for eachtraffic flow of the plurality of traffic flows, wherein selectivelyapplying bit-level bulk data compression to the plurality of trafficflows on a flow-by-flow basis comprises, for each traffic flow,selectively applying bit-level bulk data compression to the traffic flowdepending, at least in part, on the traffic flow type identified for thetraffic flow.
 6. The method of claim 1, further comprising receiving thecommunication traffic from a plurality of traffic queues, whereinselectively applying header compression to headers of traffic units fromthe communication traffic comprises selectively applying headercompression to headers of traffic units from the communication trafficon a queue-by-queue basis.
 7. The method of claim 1, further comprisingreceiving the communication traffic from a plurality of traffic queues,wherein selectively applying bit-level bulk data compression to thecommunication traffic comprises selectively applying bit-level bulk datacompression to the communication traffic on a queue-by-queue basis. 8.The method of claim 1, wherein a size of the blocks upon which thebit-level bulk data compression operates is user selectable.
 9. Anon-transitory computer-readable medium storing instructions which, whenexecuted, perform the method of claim
 1. 10. An apparatus for processingcommunication traffic comprising a plurality of traffic units, eachtraffic unit having a header and a payload, the apparatus comprising: aheader compressor to selectively apply compression to headers of trafficunits from the communication traffic; a bit-level bulk data compressor,operatively coupled to an output of the header compressor, toselectively apply bit-level bulk data compression to the communicationtraffic, wherein bit-level bulk data compression accumulates blocks ofbits, including headers and payloads of traffic units from thecommunication traffic, and operates on each block individually.
 11. Theapparatus of claim 10, wherein: the communication traffic comprises aplurality of traffic flows, each traffic flow comprising a plurality oftraffic units; and the header compressor is configured to selectivelyapply header compression to headers of traffic units from the pluralityof traffic flows on a flow-by-flow basis.
 12. The apparatus of claim 11,wherein for each traffic flow of the plurality of traffic flows, theheader compressor is configured to selectively apply header compressionto headers of traffic units from the traffic flow depending, at least inpart, on a traffic flow type identified for the traffic flow.
 13. Theapparatus of claim 10, wherein: the communication traffic comprises aplurality of traffic flows, each traffic flow comprising a plurality oftraffic units; and the bit-level bulk data compressor is configured toselectively apply bit-level bulk data compression to the plurality oftraffic flows on a flow-by-flow basis.
 14. The apparatus of claim 13,wherein for each traffic flow of the plurality of traffic flows, thebit-level bulk data compressor is configured to selectively applybit-level bulk data compression to the traffic flow depending, at leastin part, on a traffic flow type identified for the traffic flow.
 15. Theapparatus of claim 10, wherein: the communication traffic is receivedfrom a plurality of traffic queues; and the header compressor isconfigured to selectively apply header compression to headers of trafficunits from the communication traffic on a queue-by-queue basis.
 16. Theapparatus of claim 10, wherein: the communication traffic is receivedfrom a plurality of traffic queues; and the bit-level bulk datacompressor is configured to selectively apply bit-level bulk datacompression to the communication traffic on a queue-by-queue basis. 17.The apparatus of claim 16, wherein the bit-level bulk data compressor isconfigured to instantiate a plurality of bit-level bulk data compressorinstances, each bit-level bulk data compressor instance beingindividually configurable to selectively apply bit-level bulk datacompression to the communication traffic by accumulating blocks of bitsfrom at least one of the traffic queues, and operating on each blockindividually.
 18. The apparatus of claim 10, wherein the size of theblocks upon which the bit-level bulk data compressor operates is userselectable.
 19. A method of processing communication traffic comprisinga plurality of traffic units, each traffic unit having a header and apayload, the method comprising: selectively applying bit-level bulk datadecompression to the communication traffic, wherein bit-level bulk datadecompression comprises accumulating blocks of bits, including headersand payloads of traffic units from the communication traffic, andoperating on each block individually; selectively applying headerdecompression to headers of traffic units from the communicationtraffic.
 20. The method of claim 19, further comprising receivingbit-level bulk data decompression information in respect of thecommunication traffic, wherein the bit-level bulk data decompressioninformation in respect of the communication traffic is used whenselectively applying bit-level bulk data decompression to thecommunication traffic.
 21. A non-transitory computer-readable mediumstoring instructions which, when executed, perform the method of claim19.
 22. An apparatus for processing communication traffic comprising aplurality of traffic units, each traffic unit having a header and apayload, the apparatus comprising: a bit-level bulk data decompressor toselectively apply bit-level bulk data decompression to the communicationtraffic, wherein bit-level bulk data decompression accumulates blocks ofbits, including headers and payloads of traffic units from thecommunication traffic, and operates on each block individually; a headerdecompressor, operatively coupled to an output of the bit-level bulkdata decompressor, to selectively apply header decompression to headersof traffic units from the communication traffic.
 23. The apparatus ofclaim 22, wherein the bit-level bulk data decompressor is configured toreceive bit-level bulk data decompression information in respect of thecommunication traffic and use the bit-level bulk data decompressioninformation when selectively applying bit-level bulk data decompressionto the communication traffic.